decrefcere, pone; cryftallos, quas fpecimen exhibet, fin-
gulas, fob quavis magnitudine, & craflitudine, funul con-
cipies, aut etiam ortas videbis; quarum color flavo-
byalinus, citrinus, ceraceus, aut rubro - aurantiacus, vix
pifi majori, aut minori metalli heterogeijei admixts por-
tioni adfcribi poteft.
XXX.
PLUMBUM fpatofum flavum cryftallinum, cryflaUis otto-
decdedris plano-compreßs, fpato drufico, felenitico-
decaedro, ex toto, out parte/incrußatis- Tab. 21.
Fig. 1 6. Itidem ex S. Matths o.
Extimam calcarei prsedicLi faciem, bellariorum fac-
cbaro conditorum more, obducit crufta craffior fpati
calcarei cryftallino - drufici, cryftallis pellucidis, albis,
nitentibus, rhombeis, felenitico - decaedris, magnitudine
differentials, inordinate confluentibus, connatisque, ut
rariufcule integram extricare valeas, plerumque hoc aut
illo piano laterali, five angulo, ultra fuperficiem exftan-
tem, & micantem difcernas. Crufts huic, quae interduffl
lapidem ipfum, venae aut rivi msandriformis inftar pererrat,
errat, infident parcius, aut copiofius fparfs teffuls, aut
cryftalli plumbi fpatofi flavi exigus, aut majufculs, quadrats,
oftogons, rhombeo-decaedrs felenitics, ut plu-
rimum octodecaedrs piano-depreffs, haud admodum
craffs, colore citrino, diaphans, nitentes, Quod vero
fflirum maxUne, & non eodem natas tempore, evidenter
evincit, illud eft, quod earum nonnulls tots ultra me-
moratam cruftam emineant nuds, uno eidern latere oblique
aut normaliter, Temper tarnen leviflime infidentes;
alia; media, aut plusquam media fui parte intra eaindem
demerfsTint; nonnulls, five proftrats, .five erefts intra
eamdem penitus confepults, & incruftats, per transparentem
prscife drufico - cryftallinam cruftam obfcunore
colore traluceant. Vidi etiam & poffideo fpecimen, in
quo oblique exftantium cryftallorum oftodecaedrarum
pars fuperior, crufta iacchari confeftionarii velut, obdu-
cta fuit tota, parte earumdem inferiore nuda exiftente ;
manifefto utique indicio, ftillicidio materis marmoreo-
fpatofe fluids, nuper duntaxat, incruftata fuiffe cryftallorum
plumbiferarum prsexiftentium ddrfa, non partem a
ftillicidio averfam.
X X X I
§
D d 3